Conveyor chain

ABSTRACT

A conveyor chain formed of pintle-connected links wherein alternate links of the chain carry elongated roller assemblies having rollers extending longitudinally of the direction of travel of the chain and forming a supporting surface for objects to be transported and wherein each assembly is positioned on its carrying link so as to extend over and thereby be supported by a link immediately in advance of its carrying link when the chain extends in a straight line condition.

United States Patent 11113,568,822

[72] Inventors Robert D. Conkey [56] References Cited West Vancouver,British Columbia; UNITED STATES PATENTS g fg 1,641,642 9/1927 Pangborn198/183 [21] APPL No 792,474 1,745,192 1/1930 Shafer 198/183 [22] FiledJan.,21, 1969 Primary Examiner-Robert G. Sheridan [45] Patented Mar. 9,1971 AttorneyLyle G. Trorey [73] Assignee Canada Chain and Forge CompanyLtd.

Granville Island, Vancouver, Canada [54] CONVEYOR CHAIN ABSTRACT: Aconveyor chain formed of pintle-connected links wherein alternate linksof the chain carry elongated roller assemblies having rollers extendinglongitudinally of the direction of travel of the chain and fonning asupporting surface for objects to be transported and wherein eachassembly is positioned on its carrying link so as to extend over andthereby be supported by a link immediately in advance of its carryinglink when the chain extends in a straight line condition.

PATENTEUHAR 9.91.

SIEEIIBFZ Robert D. Conkey and Rupe Clement fito s Lyle Trorey,

Agent PAIENIEnm 915m 3,568,822 snttfz or 2 by Lyle G Trorey,

Ant

convnvon cnArN BACKGROUND OF THE INVENTION This invention relates tochain conveyors which are provided with longitudinally arranged rollersconstituting a supporting surface for objects conveyed by the chain.

This type of chain is commonly used in a lumber mill and the like fortransporting sawn lumber from point to point and wherein it is necessaryto withdraw the lumber in a direction which is substantially at rightangles to the direction of travel of the chain.

' It is appreciated that many and varied arrangements of this type ofconveyor chain have heretofore been devised. In some arrangements therollers are connected to each link of the chain whereas in others therollers are carried by alternate links and are cantilevered over thelinks adjacent, so as to form a substantially continuous supportingsurface broken only by the space between adjacent rollers. In thelast-mentioned type of roller chains commonly termed rolltop chains somehave been designed so that the rollers are cantilevered over botli thefore and aft pivoted connections of the carrying links with the linksimmediately in advance of and following the latter. The carryingsurfaces of all rollers will lie in the same plane. However when thechain reaches a point at which it must return over sprockets or thelike, the trailing ends of the rollers, as the rollers change direction,will lift upwardly above the general plane of the rollers in thatportion of the chain extending in a straight line condition and veryfrequently, therefore, damage the objects being carried by the chain.

In some chains of this last-mentioned type the rollers have I beencantilevered over only the link in advance of the carrying link so thatthe trailing ends of the rollers, as the chain passes over a returnsprocket of the like, will not tip upwardly to damage objects carried bythe chain. In this type of chain, however, the supporting structurecarrying the rollers extends freely over and in unsupported relationshipto the link in advance of the carrying link. As the cantilevered portionof the rollers must be almost as long as the links in advance of thecarrying links in order to make the space between adjacent rollers assmall as possible, weighty objects supported on said cantileveredportions can cause the roller-carrying links to be tilted out of astraight line condition with respect to the links adjacent thereto. Thiscan, therefore, result in damage to objects transported by the chain.

The supporting structures of the rollers of the last-mentioned type ofchain, due to the high stresses which may be set up, when the cantileverportions are subjected to heavy loads, must be of relatively heavyconstruction. This construction is not only relatively expensiverespecting manufacture but results in a relatively heavy conveyor chainwhich is difficult to handle and which requires excessive power for itsoperation.

The conveyor chain of the present invention is designed to overcome thedisadvantages of the last-mentioned type of chain. The present conveyorchain includes roller assemblies which are connected to alternate linksof the chain and which overhang the links immediately in advance of theroller carrying links. However the assemblies are so designed that withthe chain in a straight line condition they are supported not only bythe links to which they are connected but by the links immediately inadvance thereof, thereby permitting the roller assemblies to befabricated of relatively light parts.

Furthermore tipping of a roller assembly and the link to which it isconnected by the weight of a load on the overhanging or cantileveredportion thereof is effectively eliminated.

The conveyor chain of the present invention is formed of a plurality ofpintle-connected links, having longitudinally extending rollerassemblies mounted on alternate links which extend over the links inadvance of the links on which they are mounted, each said rollerassembly including an elongated roller and a base structure rotatablysupporting the roller for rotation about an axis parallel to thedirection travel of the chain, said base structure being arranged on itscarrying link so as to engage, and be supported by, the link advancethereof when chain is extended in a straight line condition.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a section ofone form of a chain embodying my invention,

FIG. 2, appearing on sheet 2 of the drawings is a top plan view of asection of the chain of FIG. 1,

FIG. 3 is a sectional view taken on line 3-3 of FIG. 1,

FIG. 4 is an isometric view of a supporting base of a roller assembly.

DESCRIPTION OF PREFERRED EMBODIMENT Referring to the drawings, and inparticular to FIGS. 1 and 2 thereof, there are shown fragments orportions of a conveyor chain 10 which includes features of invention.The fragments of the chain shown constitute an upper run portion of anendless conveyor chain which operates over head and foot sprockets (footsprockets only being shown in dotted lines in FIG. 1 and accorded thenumeral 1-1 for identification). The conveyor chain is driven bysuitable means, not shown, so that the upper run travels in thedirection as indicated by the arrow Chain 10 is formed of a plurality ofidentical links 13 three of which are shown in FIGS. 1 and 2 andaccorded the reference numeral 13.1, 13.2 and 13.3 for identification.Each link is formed of a pair of side bars 14-14 which are of the samewidth from end to end and have parallel upper 15 and lower 16 surfaces.These side bars are connected by tubular end bars 17 which extendbetween a pair of adjacent ends 18 of said side bars. The end bars 17are nonrotatably connected to their associated side bars by welding orthe like so that the upper and lower surfaces 15 and 16 of the latterextend in a common plain. The ends 19 of the side bars opposite the ends18 thereof lie in freely spaced-apart relationship.

Successive links of the chain are united by pintles 20 that pass throughcentrally located perforations through the ends 19 of the side bars andthrough the tubular end bars of connected links, in a well known manneras illustrated in the drawings.

Mounted on alternate links of the chain are roller assemblies 22 each ofwhich include a supporting base 23 and an elongated roller 24. Asillustrated in the drawings particularly in FIG. 4, the supporting baseis U-shaped and includes an "elongated flat base portion 25 which issubstantially the same width as the link width, and upstanding endportions 26. The end portions 26 are provided with apertures 27 throughwhich a pin 28 is passed, said pin being swedged or riveted at its ends.The roller 24 is mounted on the pin 28. The roller is elongated, havinga bore 30 for the passage of the pin 28, said bore being counterbored ateach end to receive bushings 32 which rotatably embrace the pin 28. Asclearly shown in FIGS. 1 and 2 the roller assemblies 22 are materiallylonger than the chain links.

Referring to FIGS. 1 and 2 it will be seen that links 13.1 and 13.3 eachcarry a roller assembly 22. The roller assembly 22, mounted on link13.1, is arranged so that the supporting base 23 extends longitudinallyof and centrally of the latter and is positioned so that the trailingend 29 of the roller 24 (relative to the direction of travel of thechain) is positioned on or very slightly in advance of the axis ofpintle 20 connecting link 13.1 to the following link. The base portion25 of the supporting base 23 fits flush against the side bars 14-14 oflink 13.1 and is rigidly secured to the latter as by welding at 33-33.As the roller assembly is materially longer than the link 13.1 thesupporting base 23 and roller 24 extend forwardly over the side bars14-14 of link 13.2. A roller assembly is also positioned on the link13.3 in the manner as hereinbefore described, slightly in advance of andspaced from the roller assembly on link 13.1 so as to provide aclearance 35.

In use the conveyor chain, as previously described, passes over head andtail sprockets, its upper run being supported by a horizontal track, notshown, on which the lower surfaces 16 of the links ride. The upper runof the chain therefore will extend in a straight line condition, asillustrated in solid lines in FIG. 1, and as the roller assemblies areidentical the longitudinal axes of the pins 28 will be aligned with eachother as will the upper peripheral surfaces of the rollers. As the baseportions of the base structures are flush and rest upon the side bars ofthe links to which they are connected, they will, consequently, extendover and rest upon the corresponding side bars of the link immediatelyin advance thereof when the chain is extended in a straight linecondition. It will be apparent therefore, that a weight imposed by aload on any roller will be transmitted, to the link upon which theroller is mounted and the link in advance thereof. As links aresupported in a straight line condition by the track upon which they ridethe rollers will not tie r tilt under vertical loading.

The positioning of each roller assembly so that trailing end thereof isslightly in advance of the pivotal'axis of the link upon which it ismounted, with the links following, will, when the chain starts to passover the foot sprocket 11, as indicated in dotted lines in FIG. 1,resulting in the trailing end of each roller following a downwardlydirected arcuate path as the link to which it is mounted starts todeflect from a straight line condition.

lt will be seen that the conveyor chain as herein described provides astraight level supporting surface for objects to be carried which isbroken only by the spaces between successive rollers.

Furthermore as the supporting bases of each of the roller assemblies areeach supported at one end by the link upon which they are mounted and atthe other end by the link in advance thereof they will not be subjectedto stresses to which they would ordinarily be subjected to if saidsupporting bases were to be supported only by the links on which theyare mounted.

We claim:

1. A conveyor chain having pintle connected links (13), each link havingside bars having flat parallel upper and lower surfaces, the chainincluding:

a. roller assemblies (22) mounted on alternate links 13) of the chain;

b. each roller assembly including a roller (24) and a base structure(23) in which the roller is mounted for rotation about an axislongitudinally of the chain; and

0. each base structure having a flat under surface and being disposed sothat its under surface extends over and rests on the upper surfaces ofthe side bars of a link immediately in advance of the link on which itis mounted so as to be supported by the link in advance when the chainis extended in a straight line.

2. Structure as defined in claim 1 wherein each supporting base isU-shaped having an elongated base portion and upturned end portions,said end portions having an elongated pin extending therebetween uponwhich the roller is mounted.

3. Structure as defined in claim 1 wherein the assembly is positioned onits carrying link so that the trailing end of each roller is positionedin advance of the pivotal connection of the link which it is mounted andthe link trailing.

1. A conveyor chain having pintle connected links (13), each link having side bars having flat parallel upper and lower surfaces, the chain including: a. roller assemblies (22) mounted on alternate links (13) of the chain; b. each roller assembly including a roller (24) and a base structure (23) in which the roller is mounted for rotation about an axis longitudinally of the chain; and c. each base structure having a flat under surface and being disposed so that its under surface extends over and rests on the upper surfaces of the side bars of a link immediately in advance of the link on which it is mounted so as to be supported by the link in advance when the chain is extended in a straight line.
 2. Structure as defined in claim 1 wherein each supporting baSe is U-shaped having an elongated base portion and upturned end portions, said end portions having an elongated pin extending therebetween upon which the roller is mounted.
 3. Structure as defined in claim 1 wherein the assembly is positioned on its carrying link so that the trailing end of each roller is positioned in advance of the pivotal connection of the link which it is mounted and the link trailing. 